It depends on what you already had & how much you want to spend. You can go the cheap route & use a cooler for a mash tun, or spend big bucks on a nice RIMS system. If you want to ease into it cost wise, start by picking up a turkey fry kit & then you'll have a burner & kettle to do a full boil. You'll also need a chiller of some type. You can build your own immersion chiller by wrapping some copper tubing around a corny ket (or something similar).

If you already have a burner & kettle, then get a cooler to build a mash tun. I made mine out of a 10 gallon drink cooler & a SS false bottom I purchased on line. If you're handy with welding, you can use a rectangular cooler & build your own manifold to keep the grain out of the sweet liquor. I'd avoid the 5 gallon coolers as you'll have a hard time fitting 16+ pounds of grain plus mash water if you ever want to do a big beer.

Pickup a copy of Charlie Papazian's "New Joy of home brewing", and read it, esspecially the "Advanced all grain section". You will learn a lot, about the techniques, and equipment necessary. I have been doing all grain for three years and still use my "Zapap" lauter tun which is outlined in this book. I read this book and the all grain section 1 year before taking the leap. I collected everything BEFORE I did my first batch, I was well prepared and it paid off BIG TIME. The equipment part was easy, the rest was formulated by the group of great guys and gals here helping me along the way, I read, asked and listened ...

You can get off pretty cheap if your are willing to do some work, and make some stuff your self, esspecially if money resources are low, like my situation

As for keeping the temp. where you want it, I use a large rectangular cooler for my mash tun, and generally I will lose 2-3 degrees (F) in the summer over 90 minutes and 5-8 degrees (F) in the winter, so I wrap it in a heavy blanket in the winter lowering my lose to 2-3 degrees per 90 minute mash, you can adjust by adding 2 cups of boiling water every so often, and stirring vigorously so is not to creat hot spots to assist in raising the temp back to target.

Previous to building the system I had done successful all-grain brewing with much lower tech equipment. I consider the 3 tier system a luxury; but having a big pot, a wort chiller and a powerful source of heat are indespensable.

Another solution is to give a try with some 'starter's kit', which is supposed to include all basic equipment needed.

This just to say that if you wan't to give a try, it won't cost hundred dollars to take pleasure with homebrewing.

Next, you'll be able to begin to learn the tips, tricks and secrets of this fabulous alchemy...

Next, there's allways a reason to improve your equipment... chillers, recirculating systems, gas burners, controllers... but i'm not sure the knowledge of brewing is only in the quality of equipment or the money you spent.